In the case of ball joints, the geometric load bearing factor, GT, enters in by the power of two. This is the reason why, especially with joints having less than the standard 6 balls, attempts are made to use balls with a larger diameter. In order to permit the inner joint part to be pivotable relative to the cage, the shaft, via a profiled journal, is normally inserted into a corresponding bore of the inner joint part.
However, there is a disadvantage in that the space available for the bore is reduced (FR-PS 1 418 233) as the size of the balls are increased. As a result, the torque transmitting capacity of the constant velocity joint is greatly reduced.
It is the object of the present invention to provide a constant velocity universal joint which comprises balls with larger diameters and in the case of which the transferable torque is not adversely affected.
In accordance with the present invention, the objective is achieved in that, in a first operation, the inner joint part and the cage are assembled at a relative pivot angle of up to 90.degree. and that subsequently, in a second operation, starting with the pre-assembled unit, the inner joint part is welded to an associated shaft.
The advantage of the method in accordance with the present invention consists in that the shaft diameter may be selected so as to correspond to the core diameter of the inner joint part.
In an advantageous embodiment of the present invention, the inner joint part and the shaft are connected to one another by friction welding.
With this friction welding process, the pre-assembled unit, including the balls, may be accommodated in an outer joint part or in a device corresponding to an outer joint part and serving to provide torque support.
According to a further feature of the present invention, the inner joint part and the shaft are connected to one another by laser welding.
The advantage of this laser welding method is that weld splatter is avoided without fail.
In a further embodiment of the present invention it is proposed that the inner joint part and the shaft should be connected to one another by electron beam welding.
This electron beam welding process, too, has the advantage of avoiding weld splatter without fail.
According to a further embodiment of the invention, the connecting end of the shaft, for welding purposes, is provided with a centrally arranged recess. The advantage of such a recess is that in the course of welding, friction is avoided in the center of the connection between the inner joint part and the shaft. This design also ensures that the shaft heats up more quickly than the inner joint part, as a result of which structure transformation in the region of the ball running grooves is avoided.